1. Field of the Invention
The present invention relates to electrical connectors and, more particularly, to an electrical connector having grounding means for transient high voltage pulses.
2. Description of the Prior Art
Transient voltage pulses of electromagnetic radiation (EMP) are known to result from lightning and nuclear explosions. Such pulses can detrimentally affect solid state circuitry in precision instruments, communication systems and computer components. To protect the sensitive circuitry, metal housings and compartments have been used to ground the EMP. However, most all housings and compartments are still vulnerable because they are penetrated by connectors that link electrical cable which serve as pathways for EMP.
To overcome the above vulnerability, connector devices have evolved which contain EMP diversion means. U.S. Pat. No. 3,702,402 discloses an electrical connector having connector pins coated with a dielectric material to a thickness of 0.005 to 0.030 inch. The dielectric material functions to stimulate arcing across the end of the material from the connector pin to a grounded shell.
The patented device requires an arc-over discharge chamber and the end of the dielectric material must be flush with an adjacent conductive surface. Otherwise, arcing at the desired voltage level will not occur. Venting ports are used with the discharge chamber and, in the case of a high-current lightning strike, the connector pins may explode and deposit molten metal about the chamber. This shorts the pins to the grounded shell and is described as providing fail-safe protection.
A semiconductor diode is used in U.S. Pat. No. 4,572,600 to divert EMP to a ground plane. Here, a notch in a connector pin is provided with a diode which is secured by a circumferential band. A surrounding spring holds the band and diode in place. In it also in electrical contact with a ground plane. EMP transients are thereby diverted from the pin by the diode, then to the band, spring and finally to the ground plane. An important function of the above multi-part assembly is to assure uninterrupted electric contact during exposure to shock and vibration.